Photographic processing apparatus



Sept. 9, 1969 w. J. CALDER 3,465,663

PHOTOGRAPHIC PROCESSING APPARATUS Filed Sept. 19, 1966 United States Patent 3,465,663 PHOTOGRAPHIC PROCESSING APPARATUS William John Calder, Ilford, England, assignor to Ilford Limited, Ilford, Essex, England, a British company Filed Sept. 19, 1966, Ser. No. 580,268 Claims priority, application Great Britain, Sept. 23, 1965, 40,619/ 65 Int. Cl. G03d 3/12 US. Cl. 95--89 Claims ABSTRACT OF THE DISCLOSURE A photographic processing apparatus having a pair of juxtaposed treating vessels containing an activator solution and a stabilizer solution respectively, a plurality of applicator rollers associated with each of the treating vessels for applying the treating solution to a photographic material which comes into tangential contact with the rollers, and a drive mechanism for rotating the rollers. The first applicator roller in the stabilizer vessel is made of a smooth surfaced material and rotates at a peripheral speed which is greater than that of the other rollers in the stabilizer vessel and in a direction which is opposite to the direction of rotation of the other rollers in the vessel. The other rollers are made of a non-smooth surfaced material which serves to transport the photographic material through the treating vessel as well as apply solution thereto.

This invention relates to photographic processing apparatus and in particular to apparatus for processing gelatino silver halide photographic sheet materials for use in offices and the like.

A known process of producing photographic: prints is to employ as the print material a material which carries a layer of a photographic silver halide emulsion which contains a photographic developing agent, imagewise expose the material, treat it with an alkali bath in order to activate the development (a so-called activator bath) thereby producing a silver image in the material, and then treat the material with a bath (a so-called stabiliser bath) containing a substance which, by complexing with the residual silver halide in the material inhibits its lightsensitivity, thus stabilizing the photographic print thus obtained. The present invention relates to an improvement in the apparatus used in the said process which for convenience is hereinafter referred to as a process of the type defined.

It is possible to carry out a process of the type defined by feeding the exposed print material through a system of rollers which apply to it, successively, the activator solution and the stabiliser solution, thus rendering possible the production of prints in a rapid and reliable manner.

Apparatus have been proposed in which two or more rollers are mounted in the activator bath and two or more rollers are mounted in the stabiliser bath each of the rollers being partially immersed in the solution in the two baths. Exposed photographic material is passed over the rollers emulsion face downwards so that the first solution activates the developer in the material and the second solution stabilises the developed image. Whilst a sufiicient degree of the development of the image may be obtained over a very short period of contact with the activator solution, e.g., a contact period of, say, 3 seconds, full development of the image may take considerably longer, e.g., 12 seconds. It is accordingly usual to process the material in contact with the activator for less than the period required for full development and then pass ice it over the stabiliser applicator rollers. This means that, as the development stops as soon as the material comes in contact with the stabiliser solution, due to the sudden drop in pH caused by the stabiliser solution, all the material should be arranged to come in contact with the stabiliser solution having received exactly the same development time. If this is not achieved, local overdevelopment or under-development will occur.

It is the object of the present invention to provide an apparatus for use in a stabilisation process of the type defined whereby improved photographic prints may be obtained.

According to the present invention there is provided a processing apparatus for use in a stabilisation process of the type defined, which comprises juxtaposed vessels for activator solution and for stabiliser solution, a sequence of rollers comprising at least two rollers associated with each said vessel and disposed to rotate in contact with solution in said vessel so as to pick up solution therefrom and bring it into contact with photographic material fed over and in tangential contact with the sequence of rollers, whereby first activator solution and then stabiliser solution is brought into contact with the photographic material, that roller associated with the vessel containing stabiliser solution which is earliest in the said sequence having a smooth surface and other rollers of the sequence having a non-smooth surface and serving to transport the photographic material through the apparatus, and means for driving the said rollers, and including means for driving the said smooth-surfaced roller at a peripheral speed which is substantially greater than the peripheral speed at which the remainder of the rollers are driven.

In the preferred form of the invention the apparatus is used at driving speeds in which the peripheral speed of rotation of the said smooth-surfaced roller is at least four times the peripheral speed of the remainder of the rollers of the sequence. In one preferred embodiment of the invention the peripheral speed of rotation of the said smooth-surfaced roller is eight times the peripheral speed of the remainder of the rollers of the sequence.

The roller which rotates at a substantially greater speed than the remainder of the rollers and which is smooth covered acts only a solution applicator roller and does not serve to drive forward photographic material being processed in the apparatus. Thus this roller may rotate in the same direction as the remainder of the rollers in the sequence or it may rotate in a contra-direction.

In one embodiment of the invention all the rollers except the roller which rotates at the higher peripheral speed are covered with rubber and the roller which rotates at the higher peripheral speed is a polished stainless steel roller.

In the preferred method of use of the apparatus of the invention, the rubber covered rollers are 1.7 to 2.0 cm., preferably 1.9 cm. in diameter and rotate at 30 to 60, e.g., 40 r.p.m. and the stainless steel roller is of the same diameter and rotates at 240-480, e.g., 320 r.p.m.

Where there are more than two rollers associated with the stabiliser vessel the second or a subsequent roller may also be a smooth-surfaced roller, e.g., a stainless steel roller which revolves at a higher peripheral speed but sufiicient other rollers, e.g., nibber covered rollers must be present to drive the photographic material through the apparatus. In apparatus of this type either or both of the smooth-surfaced rollers may be contra-rotating.

Using apparatus of this type a photographic print is obtained in which the development is of improved uniformity. This improvement in the photographic print quality is obtained because a large amount of stabiliser is applied to the developed material by the fast rotating stainless steel roller, which carries on its surface a relatively large amount of the stabiliser solution due to its high speed of rotation. This roller, being smooth surfaced, does not tend to drive the photographic material as do the other rollers and does not, therefore, cause fluttering or uneven drive of the photographic material (which when present tends to cause processing marks to appear on the print).

One embodiment of the invention is illustrated in the accompanying drawing which is a diagrammatic side elevation of the apparatus.

Referring to the drawing, the apparatus comprises an activator bath 1 which contains an activator solution 2. Dipping into this bath are three rubber covered rollers 3 which are driven at 50 r.p.m. Next to the activator bath is a stabiliser bath 4 which contains stabiliser solution 5. In the bath 4 there is a stainless steel roller 6 which is driven at 400 r.p.m. and also two rubber covered rollers 7 which are driven at 50 r.p.m. All the said rollers are of 1.9 cm. diameter. Above the two baths 1 and 4 there is a guide 8 which serves to keep the photographic material in contact with the upper surfaces of the rotating rollers.

Exposed photographic material is introduced into the apparatus at 9. The rollers 3 which are rotating in the activator solution coat the material with the activator solution which activates the developer contained in the photographic material and so initiates development. The partially developed photographic material is urged forward by the rubber covered rollers 3 on to the stainless steel roller 6 whose surface is covered with stabiliser solution. The stabiliser solution, being of low pH, immediately stops development uniformly across the width of the photographic material. Further stabilising solution is applied by the rubber covered rollers 7 and the material emerges from the apparatus sufiiciently developed and fully stabilised.

I claim as my invention:

1. In a photographic material processing apparatus for use in a stabilization process of the type defined which comprises juxtaposed vessels for activator solution and for stabilizer solution, a sequence of rollers comprising at least two rollers associated with each vessel so as to pick up solution therefrom and bring it into contact with photographic material fed over and in tangential contact with the sequence of rollers, whereby first activator solution and then stabilizer solution is brought in contact with the photographic material and means for driving the said rollers, the said sequence of rollers including rollers of non-smooth surface which serve to transport the photographic material through the apparatus, the improvement which comprises providing that there are rollers of nonsmooth surface and rollers of smooth surface associated with the vessel containing the stabilizer solution, and the roller which is earliest in the said sequence has a smooth surface and that there is provided means for driving the said smooth surfaced roller at a peripheral speed which is substantially greater than the peripheral speed at which the remainder of the rollers are driven, and the direction of rotation of said smooth-surfaced roller is contra to the direction of the remainder of the rollers.

2. A processing apparatus according to claim 1 wherein the said means for driving the said smooth-surfaced roller provides that the peripheral speed thereof is at least four times the peripheral speed at which the remainder of the rollers are driven.

3. A processing apparatus according to claim 1 wherein the said means for driving the said smooth surfaced roller provides that the peripheral speed thereof is substantially eight times the peripheral speed at which the remainder of the rollers are driven.

4. A processing apparatus according to claim 1 wherein the smooth-surfaced roller is of stainless steel having a highly polished surface.

5. A processing apparatus according to claim 1 wherein the non-smooth surfaced remainder of the rollers are rubber covered.

6. In a processing apparatus for use in a stabilization process of the type defined which comprises juxtaposed vessels for activator solution and for stabilizer solution, a sequnece of rollers which comprises at least two rollers associated with the activator solution and at least three rollers associated with the stabilizer solution vessel and disposed to rotate in contact with the solution in each vessel so as to pick up solution therefrom and bring it into contact with the photographic material fed over and in tangential contact with the sequence of rollers, whereby first activator solution and then stabilizer solution is brought in contact with the photographic material and means for driving the said rollers and other rollers of said sequence having a non-smooth surface and serving to transport the photogrphic material through the apparatus, the improvement which comprises providing that there are rollers of non-smooth surface and rollers of smooth surface associated with the vessel containing the stabilizer solution, and the roller which is earliest in the sequence and one other roller associated with the vessel containing the stabilizer solution are each provided with a smooth surface and that there is provided means for driving the said smooth-surfaced rollers at a peripheral. speed which is substantially greater than the peripheral speed at which the remainder of the rollers are driven, the direction of rotation of said smooth-surfaced roller which is earliest in sequence is contra to the direction of rotation of the remainder of the rollers.

7. A processing apparatus according to claim 6 wherein the said means for driving the said smooth-surfaced rollers provides that the peripheral speed thereof is at least four times the speed at which the remainder of the rollers are driven.

8. A processing apparatus according to claim 6 wherein the said means for driving the said smooth-surfaced roller provides that the peripheral speed thereof is substantially eight times the peripheral speed at which the remainder of the rollers are driven.

9. A processing apparatus according to claim 6 wherein the smooth-surfaced rollers are of stainless steel having a highly polished surface.

10. A processing apparatus according to claim 6 wherein the non-smooth surfaced remainder of the rollers are rubber covered.

References Cited UNITED STATES PATENTS 2,333,902 11/ 1943 Thiele et al. 118-223 3,354,807 11/1967 Horner 89 XR FOREIGN PATENTS 1,392,326 2/ 1965 France.

960,413 6/1964 Great Britain.

NORTON ANSHER, Primary Examiner FRED L. BRAUN, Assistant Examiner U.S. Cl. X.R. 118223 

